High Power ICRH scenarios in Tore-Supra: a potential route towards improved core confinement at high density?

Abstract

Before the complete refurbishment of the Tore-Supra inner vessel in 2000-2001, an experimental scenario had been successfully developed which achieved low/negative magnetic shear in the plasma core by means of a very fast current ramp-up. With up to 4 MW of ICRH power, in (H)He4 minority electron heating, a region of reduced core transport was transiently observed, leading to a strong increase of the core electron pressure [1]. This scenario is potentially well suited for studies of Internal Transport Barrier triggering and sustainment. Experiments in such conditions have been recently resumed with the aim of expanding the operational parameter range towards higher density and higher levels of injected power.